Differences in sensitivity to neuroleptic blockade: medial forebrain bundle versus frontal cortex self-stimulation.
The effects of systemic injections of the dopamine receptor antagonist, cis-flupenthixol were tested on intracranial self-stimulation at electrode sites in the medial forebrain bundle and the medial prefrontal cortex. Changes in the reward effectiveness of the brain stimulation were assessed using a curve-shift paradigm. Low to moderate doses of cis-flupenthixol (0.05, 0.1 and 0.15 mg/kg) consistently produced larger upward shifts in the rate-frequency function for medial forebrain bundle than for medial prefrontal self-stimulation. At the highest doses of cis-flupenthixol (0.15 and 0.2 mg/kg), some of the medial forebrain bundle rats failed to respond, whereas all medial prefrontal rats responded at these doses. These results demonstrate that medial forebrain bundle self-stimulation is much more dependent on dopamine systems than is prefrontal cortex self-stimulation.
Corbett
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Division of Basic Medical Sciences, Memorial University of Newfoundland, St. John's, Canada.
D000818:Animals; D001143:Arousal / Q000187:drug effects; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005475:Flupenthixol / Q000494:pharmacology*; D005625:Frontal Lobe / Q000187:drug effects*; D008297:Male; D008474:Medial Forebrain Bundle / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D012653:Self Stimulation / Q000187:drug effects*; D013892:Thioxanthenes / Q000494:pharmacology*
D011954:Receptors, Dopamine; D013892:Thioxanthenes; D005475:Flupenthixol; D004298:Dopamine